A broadband wave-absorbing metamaterial based on SLA light-cured 3D printing and a preparation method thereof

Abstract

The application discloses a broadband wave-absorbing metamaterial based on SLA light-curing 3D printing and a preparation method thereof, and belongs to the field of artificial electromagnetic metamaterial wave absorption. The preparation method of the broadband wave-absorbing metamaterial in a centimeter wave band based on SLA light-curing 3D printing comprises the following steps: (1) first, a large-area hyperbolic columnar polymer template and a flat polymer template are obtained by means of SLA light-curing 3D printing technology; (2) a metal Au layer is covered on the 3D printing template by means of magnetron sputtering technology; and (3) finally, the redundant Au on the template is removed by etching liquid, so that the hyperbolic columnar centimeter wave band wave-absorbing metamaterial is obtained. The structure disclosed by the application realizes broadband wave absorption by using single photosensitive resin material and a metal Au layer, avoids the processing difficulty of multi-layer film coating of a traditional multi-layer broadband wave-absorbing body, simplifies the parameter design between multi-layer wave-absorbing structure layers, and reduces the manufacturing difficulty.

Description

TECHNICAL FIELD

[0001] The application relates to a preparation method of a wave-absorbing material, in particular to a hyperbolic centimeter wave band broadband wave-absorbing metamaterial based on SLA light curing 3D printing and a preparation method. BACKGROUND

[0002] With the rapid development of electronic science and technology, the application range of electromagnetic wave-absorbing metamaterials is wider and wider, and the electromagnetic wave-absorbing metamaterials have important application value in fields such as fighter planes, missiles, warships, consumer electronics, communication, building, hospital and civil airport. People's requirements for the wave-absorbing performance of wave-absorbing materials are increasingly improved, and seeking a preparation method of a wave-absorbing metamaterial with high absorption rate, lightness, thinness and strong stability has become a research hotspot and focus. However, the traditional wave-absorbing device has problems such as large thickness and weight, poor stability, material consumption due to the design of a multilayer structure, and the processing difficulty of multilayer coating and the trouble of parameter design between layers of the multilayer structure are influenced by manufacturing challenges and design complexity.

[0003] At present, micro-nano metamaterial devices are mainly prepared by means of focusing ion beam decoration, electron beam decoration, photolithography technology and nano-imprinting equipment. However, such metamaterial preparation technologies not only have slow sample processing rate and high cost, but also have low adhesion and mechanical properties between layers of the metamaterial. SUMMARY

[0004] The main purpose of the application is to provide a hyperbolic centimeter wave band broadband wave-absorbing metamaterial preparation method based on SLA light curing 3D printing, so as to reduce the manufacturing difficulty and structural design complexity of the wave-absorbing metamaterial and realize high absorption of the centimeter wave band.

[0005] The preparation method of the hyperbolic centimeter wave band broadband wave-absorbing metamaterial based on SLA light curing 3D printing in the application comprises the following steps:

[0006] Step one, a polymer template with a hyperbolic columnar convex structure and a flat polymer template with the same length and width are obtained by means of SLA light curing 3D printing technology;

[0007] Step two, a metal material is covered on the front and back surfaces of the polymer template with the convex structure obtained in step one by means of magnetron sputtering technology;

[0008] Step three, then the remaining metal is corroded by using an etching liquid on the basis model obtained in step two, so as to form a hyperbolic centimeter wave band wave-absorbing metamaterial template with a metal layer on the top; and the obtained template is stacked and fixed with the flat polymer template in step one.

[0009] Further specifying, the hyperbolic raised template described in step one has a bottom thickness of 4mm, a raised height of 2mm, a top width of 14mm, and a rectangular horizontal bar width of 16mm; the flat template has a thickness of 4mm.

[0010] Further specifying, the metallic material mentioned in step two is gold (Au).

[0011] The beneficial effects of this invention are:

[0012] Combining SLA photopolymerization 3D printing with a single photosensitive resin and metal material simplifies the parameter design between multi-layer structures and reduces manufacturing difficulty.

[0013] The design exhibits a significant wideband absorption response in the centimeter wave band. CST electromagnetic simulation shows that the absorption rate of the design can reach more than 80% in the 21.4GHz-27.6GHz band. Attached Figure Description

[0014] The invention will now be described in more detail with reference to embodiments and the accompanying drawings.

[0015] Figure 1 This is a 3D structural diagram of a hyperbolic absorber;

[0016] Figure 2 The figure shows a side view of the unit cell structure of the hyperbolic absorbing material: the thickness of the upper and lower substrates Sh = 4 mm, the height of the hyperbolic protrusion is 2 mm, the cell side length is 20 mm, and the hyperbolic protrusion and the bottom are covered with a metal Au material layer.

[0017] Figure 3 This is a top view of the bottom and middle layers of the unit cell structure of the hyperbolic microwave absorbing material. The specific shape parameters are shown in the figure.

[0018] Figure 4 It is a hyperbolic simulated structure obtained from simulation;

[0019] Figure 5 It is a 3D printed hyperbolic raised polymer template and a flat template;

[0020] Figure 6 It is the simulated absorption curve of the hyperbolic convex structure;

[0021] Figure 7 The simulation diagram shows a hyperbolic centimeter-wave broadband absorbing metamaterial with a substrate portion formed by covering the hyperbolic protrusion and the bottom of the substrate with metallic Au material on the 3D printed hyperbolic protrusion and stacking and fixing it with a flat template.

[0022] Figure 8 This is a schematic diagram of the spatial geometry of a hyperbolic centimeter-band broadband absorbing metamaterial based on SLA photopolymerization 3D printing.

[0023] Figure 9 This is a real-world image showing the fabrication process of SLA-cured 3D printed microwave absorbing metamaterials. Detailed Implementation

[0024] To make the methods and technical solutions of this invention clearer, the technical solutions and performance indicators of this invention will be described in more detail below with reference to the accompanying drawings.

[0025] like Figure 1 As shown, a metal is used as the conductor layer, and a photosensitive resin material is used as the dielectric layer. The absorber consists of a large-area dielectric layer and a metal layer covering it. Therefore, this application uses only one type of photosensitive resin material when designing the overall absorber structure, and only covers the corresponding area with a metal Au layer, without the need for multiple layers of coating, and also without considering the influence of the thickness of each layer.

[0026] Figures 4-7 This is a 3D printing technology roadmap for hyperbolic centimeter-band broadband microwave absorbing metamaterials based on SLA photopolymerization 3D printing. The preparation method of this broadband microwave absorbing metamaterial is as follows:

[0027] (1) Using SLA photopolymerization 3D printing technology, large-area hyperbolic raised polymer templates and flat templates are obtained;

[0028] (2) The top and bottom of the raised template obtained in step one are covered with a metal (Au) layer by magnetron sputtering technology;

[0029] (3) Use an etchant to corrode the metal layer at the root of the raised template.

[0030] (4) Stack the two templates obtained above and reinforce them.

[0031] In step (1), the cell parameters of the hyperbolic protruding polymer template are as follows: Figure 2 As shown, the cell substrate has a side length of 20mm, a substrate thickness of 4mm, and a raised structure height of 2mm; Figure 3 As shown, the hyperbolic protrusion has a top length of 14mm and a curve equation of Y2-X2=1; the rectangular protrusion has a length of 16mm and a width of 1mm; the cells are arranged in a rectangular array with a horizontal period and a vertical period of 20mm.

[0032] In step (2), the thickness of the Au film in the simulation will not affect the absorption spectrum. Therefore, apart from magnetron sputtering, other applicable coating methods can be used. At the same time, considering that the excess Au layer on the raised side of the substrate will be etched with an etchant in step (3), the raised side should be coated and etched first, and the other side should be coated after the Au layer on that side has been formed and stabilized.

[0033] Step (4) involves stacking two boards. From a design perspective, a support structure should be added between the boards. However, in actual manufacturing, the protruding structure between the boards can fully provide support and has good overall structural stability.

[0034] In order to test and verify the absorption capability of the microwave absorber, Figure 1 The structure shown was simulated using three-dimensional frequency domain integration (CST) with a plane wave incident from the -z direction. Periodic boundary conditions were applied in the x and y directions, while an open-domain boundary condition was used in the z direction. CST frequency domain solver simulations revealed that the structure exhibits an absorption rate exceeding 80% in the 21.4 GHz–27.6 GHz range. Figure 6 As shown by the curve.

[0035] like Figures 8-9 As shown, a 3D model of the broadband absorbing metamaterial was created in the electromagnetic simulation software CST, and then the model was printed in an SLA stereolithography 3D printer. The actual printing process is as follows. Figure 9 As shown.

[0036] As can be seen, the metamaterial absorbing structure described in this embodiment has excellent absorption performance and broadband absorption advantages. This is because there are four independent metal units in each cell, which can generate multiple modes of electromagnetic resonance; at the same time, electromagnetic resonance also occurs between cells, thereby forming multiple absorption curves, which are superimposed to achieve broadband absorption.

[0037] The absorber described in this application uses the same photosensitive resin material for its overall structure, and covers the top of the hyperbolic protrusion and the bottom of the substrate with a metal Au layer, which can maximize the absorption capacity of the structure.

[0038] In summary, this application is designable, has a simple fabrication process, low production cost, and is suitable for the actual manufacturing of large-area metasurface structures.

[0039] While the invention has been described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the invention. Therefore, it should be understood that many modifications can be made to the exemplary embodiments, and other arrangements can be designed without departing from the spirit and scope of the invention as defined by the appended claims. It should be understood that different dependent claims and features described herein can be combined in ways different from those described in the original claims. It is also understood that features described in conjunction with individual embodiments can be used in other described embodiments.

Claims

1. A method for preparing broadband microwave absorbing metamaterials based on SLA photopolymerization 3D printing, characterized in that, The preparation method described above is accomplished through the following steps: Step 1: Use SLA photopolymerization 3D printing technology to obtain a polymer template with a hyperbolic columnar protrusion structure and a flat polymer template with the same length and width. Step 2: The polymer template with raised structure obtained in Step 1 is coated with metal material on both sides using magnetron sputtering technology to obtain the basic model; the metal Au layer is then formed on both sides of the polymer template with raised structure using the magnetron sputtering coating method. Step 3: Using an etchant to etch away excess metal from the base model obtained in Step 2, a hyperbolic centimeter-wave absorbing metamaterial template with a metal layer on top is formed; then the hyperbolic centimeter-wave absorbing metamaterial template is stacked and fixed with the flat polymer template from Step 1.

2. The preparation method according to claim 1, characterized in that, The ink material used in the SLA photopolymerization 3D printing technology used in step one is photosensitive resin. At a frequency of 100GHz, its dielectric constant ε=2.6+j0.0837; at a frequency of 200GHz, its dielectric constant ε=2.5+j0.05718.

3. The preparation method according to claim 1, characterized in that, The two polymer templates obtained in step two have the following structural features: Hyperbolic polymer template cell parameters: cell substrate side length 20mm, substrate thickness 4mm, and protrusion structure height 2mm.

4. The preparation method according to claim 1, characterized in that, In step three, a liquid that corrodes the metal layer is used to form a wetted protrusion at the root of the metal layer, corroding the excess metal Au layer and leaving only the top of the protrusion and the metal Au layer on the back of the substrate.

5. The preparation method according to claim 1, characterized in that, After obtaining the formed hyperbolic centimeter-band absorbing metamaterial template, it is aligned and stacked with another flat template from step one and fixed to form a three-layer sandwich structure, with the upper and lower layers being substrates and the middle layer being a hyperbolic electromagnetic resonant unit.

6. A broadband absorbing metamaterial prepared by the method for preparing broadband absorbing metamaterials based on SLA photopolymerization 3D printing as described in claim 1, characterized in that, It includes a three-layer sandwich structure, with the top and bottom layers being substrates and the middle layer being a polymer template with a hyperbolic columnar protrusion structure.

7. The broadband absorbing metamaterial based on SLA photopolymerization 3D printing according to claim 6, characterized in that, The parameters of the protrusion structure are as follows: the top length of the hyperbolic protrusion is 14mm, and the hyperbola equation is Y2-X2=1; the rectangular protrusion has a length of 16mm and a width of 1mm.

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